题目

完形填空 Denny Crook was a famous photographer. He traveled all over the world, taking picture for magazines and newspapers, and won many prizes.        “I’ll do anything to get a good photo,” he often said. “I’ll go anywhere at any time, even if it is ___1___.” And he told the ___2___. He had a photo of earthquakes, forest fires, floods and even wars. If something interesting happened, Denny went to photo it.        He was a married man and his wife often asked him to take her with him, but he always ___3___. “I’ll travel for my work, not for ___4___,( 14 分)在元素周期表中，锌（30Zn）、镉（48Cd）、汞（80Hg）同属于锌族，锌和汞在自然界中常共生，镉的金属活动性介于锌和汞之间。湿法炼锌过程中产生的铜镉渣中含有Cu、Cd、Zn等多种金属，可用于生产金属镉。镉的主要用途可以用作镍―镉电池，以及用于颜料生产，镉化合物还在PVC稳定剂、发光材料、半导体材料、杀菌剂等方面有广泛的应用。镉的生产流程如图示意如下：请回答下列问题：（1）镉元素位于周期表中第     周期，第     族，其原子结构示意图为         ；（2）写出步骤①反应的离子方程式                              。（3）步骤②所加入的金属是              。（4）步骤④用“溶液2”作电解液，镉在          极析出，该电极材料是（5）“电解废液”中含有镉，不能直接作为污水排放。目前含镉的废水处理的方式有两种，一种是在含镉污水中加入硫化钠，沉淀镉离子，另一种是加入聚合硫酸铁和聚合氯化铝，沉淀镉离子。写出硫化钠沉淀镉离子的离子方程式                     。